Traditional RDMA allows data to move directly from the memory of one computer into that of another without involving either one's CPU (central processing unit), and specifically, either one's operating system. This permits high-throughput, low-latency networking by eliminating the need to copy data between application memory and the data buffers in the operating system.
A virtual computing environment refers to a computer system in which a single physical machine may be observed as multiple virtual machines, and where a set of physical hardware resources can be used as multiple virtual resources. Each virtual machine can run its own operating system that may control the set of virtual hardware resources.
Typically, data transfer between two virtual machines passes through a virtual network device. However, virtualization of certain devices may introduce considerable overhead.